Background : Auditory evoked potentials(AEPs) have assumed an essential role in the clinical practice of auditory and several other professions. AEP classification and nomenclature systems are generally based on such aspects as the time
domain(short,
middle, long), anatomic origin, stimulus-response relationship. The P300 component of the human event related potential is an endogenous positive wave with a latency of 300msec or greater. Objectives : Our purpose of this study was to estimate
normal
values of auditory late response(ALR) and P300 in adults and use them in mapping of the brain. Materials and Methods : An auditory evoked potential was performed on 40 normal adults, and a scalp surface electrode with 30 electrodes was attempted.
Forty
adults with normal hearing were divided into 2 groups, one consisting of thirty persons under 30 years of age and the other consisting of ten persons over 30 years of age. Results : The latencies of P1, N1, P2, N1-P2 were 53.17 19.57msec, 98.25
32.68msec, 166.12 44.0msec, 65.12 23.68msec, respectively, in the whole group and 54.23 20.86msec, 98.7 34.35msec, 160.93 44.02msec 62.23 25.36msec, respectively, in the group under 30 years old, and 50.0 15.57msec, 96.9 28.69msec, 181.7
42.28msec
73.8
15.69msec, respectively, in the group over 30 years old. The P300 latencies for the whole group and the two groups were 299.37 34.01msec, 295.16 33.36msec, 312.0 34.49msec, respectively. There was no significant difference in the latency and
amplitude
of the ALR and P300 between the two groups(p>0.05). Conclusion : ALR and P300 were measured in 40 normal adults. Description of the normal topography of P300 may facilitate the examination of the P300 topography in cognitive disorders. Such an
examination might help ALR and P300 to serve as better diagnostic tools of cognitive disorder in adults.
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